Chapter 4 Synthesis of molecular tweezers and clips by the use of a molecular lego set and their supramolecular functions

Klärner, Frank‐Gerrit; Kuchenbrandt, Mireia Campañá

doi:10.1016/s1874-6004(08)80008-1

Cited by 6 publications

(5 citation statements)

References 79 publications

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“…F.-G. K. thanks the colleagues, postdocs, and students cited in the references [2][3][4][5][6][7][8][9][10][11][12][13][14] for the highly stimulating and fine collaboration.…”

Section: Acknowledgmentsmentioning

confidence: 99%

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Effect of molecular clips and tweezers on enzymatic reactions by binding coenzymes and basic amino acids

Klärner

Schräder

Polkowska

et al. 2010

Pure and Applied Chemistry

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The tetramethylene-bridged molecular tweezers bearing lithium methanephosphonate or dilithium phosphate substituents in the central benzene or naphthalene spacer-unit and the dimethylene-bridged clips containing naphthalene or anthracene sidewalls substituted by lithium methanephosphonate, dilithium phosphate, or sodium sulfate groups in the central benzene spacer-unit are water-soluble. The molecular clips having planar naphthalene sidewalls bind flat aromatic guest molecules preferentially, for example, the nicotinamide ring and/or the adenine-unit in the nucleotides NAD(P) + , NMN, or AMP, whereas the benzene-spaced molecular tweezers with their bent sidewalls form stable host-guest complexes with the aliphatic side chains of basic amino acids such as lysine and argenine. The phosphonate-substituted tweezer and the clips having an extended central naphthalene spacer-unit or extended anthracene and benzo[k]fluoranthene sidewalls, respectively, form highly stable self-assembled dimers in aqueous solution, evidently due to non-classical hydrophobic interactions. The phosphate-substituted molecular clip containing naphthalene sidewalls inhibits the enzymatic, ADH-catalyzed ethanol oxidation by binding the cofactor NAD + in a competitive reaction. Surprisingly, tweezer-bearing phosphate substituents in the central benzene spacer-unit are more efficient inhibitors for the ethanol oxidation than the correspondingly substituted naphthalene clip, even though the tweezer does not bind the cofactor NAD + within the limits of detection. The phosphate-substituted naphthalene clip is, however, a highly efficient inhibitor of the enzymatic oxidation of glucose-6-phosphate (G6P) with NADP + catalyzed by glucose-6-phosphate dehydrogenase (G6PD), whereas the phosphonate-substituted clip only functions as an inhibitor by forming a complex with the cofactor. Detailed kinetic, thermodynamic, and computational modeling studies provide insight into the mechanism of these novel enzyme inhibition reactions.

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“…F.-G. K. thanks the colleagues, postdocs, and students cited in the references [2][3][4][5][6][7][8][9][10][11][12][13][14] for the highly stimulating and fine collaboration.…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…To answer this question, the parent and the diacetoxy-substituted tetramethylene-bridged tweezers 1,2 and the tri-and dimethylene-bridged clips 3-6 (R = H, OAc, Fig. 1) were synthesized [2]. These molecules are well preorganized because of their belt-type structures.…”

Section: Introductionmentioning

confidence: 99%

Effect of molecular clips and tweezers on enzymatic reactions by binding coenzymes and basic amino acids

Klärner

Schräder

Polkowska

et al. 2010

Pure and Applied Chemistry

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“…Recently, we have described the synthesis and some supramolecular properties of a family of host molecules termed molecular tweezers and clips that are well preorganized due to their belt‐type concave–convex topography (Figure 1). 2 They preferentially bind electron‐deficient aromatic and aliphatic guest molecules as well as organic cations inside the host cavity by using aromatic π–π and CH–π interactions as dominating noncovalent binding forces 3. Electron‐rich guest molecules are not bound by these molecular tweezers and clips.…”

Section: Introductionmentioning

confidence: 99%

Donor/Acceptor‐Substituted Chiral Molecular Clips – Synthesis and Host–Guest Complex Formation

et al. 2012

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The synthesis, separation, and characterization of some substituted stereoisomeric dimethylene‐bridged molecular clips bearing donor or acceptor groups at the tips of the naphthalene sidewalls and two acetoxy, hydroxy, or methoxy groups at the central benzene spacer unit are reported. The host–guest complex formation was studied for these substituted molecular clips as host molecules with 1,2,4,5‐tetracyanobenzene (TCNB), N‐methyl‐p‐(methoxycarbonyl)pyridinium iodide (Kosower's salt, KS), and N‐methylnicotinamideiodide (NMNA) as guest molecules. The binding constants, Ka, and the complexation‐induced 1H NMR shifts of the guest signals, Δδmax, obtained by NMR titration experiments, are compared with those reported for the parent diacetoxybenzene, hydroquinone, or dimethoxybenzene clips. The diacetoxybenzene clip, bearing donor pyrrolidinyl groups at the tips of both naphthalene sidewalls, forms the most stable complexes with TCNB and KS, overwhelming the corresponding complexes of the parent clip and the clips bearing one nitro or methoxycarbonyl group at the tip of one naphthalene sidewall. The clips bearing two acceptor groups (two nitro or methoxycarbonyl groups) at the tips of both naphthalene sidewalls do not form any complex with TCNB, KS, or NMNA within the limits of NMR detection. The large complexation‐induced 1H NMR shifts of the guest signals provide good evidence that in each complex the guest molecule is clipped between the naphthalene sidewalls of the host molecule by attractive aromatic π–π and CH–π interactions, as suggested by force‐field calculations. This structural assignment of the complexes is further confirmed by a single‐crystal structure of the KS complex of the mono‐nitro‐substituted clip, which resembles the complex structure of the parent clip with KS. The good correlation between the clip's electrostatic potential surface (EPS; calculated by DFT for the donor‐ or acceptor‐substituted molecular clips) and the host–guest complex stability confirms the assumption that in chloroform solution the host–guest binding (resulting from attractive aromatic π–π and CH–π interactions) is largely electrostatic in nature, whereas the EPS values do not correlate with the binding constants found in methanol solution, indicating that additional binding forces (resulting for example from solvophobic effects) contribute to the host–guest binding. The separated optically active diacetoxybenzene clips substituted by one or two methoxycarbonyl groups at the naphthalene sidewalls are a good starting point for future studies of chiral molecular recognition and organic catalysis.

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“…In 2008, we identified more than 500 articles after searching Web of Science, PubMed, SciDir and OVID databases using ‘isothermal AND titration AND calorimetry’ or ITC or ‘Isothermal Titration Calorimetry’ search terms. Following the format of previous annual surveys these have been classified into the following categories: References cited in the text and review articles 1–82. Protein–protein and protein–peptide interactions 83–222. Protein–small ligand or protein–drug interactions 223–321. Protein/peptide metal interactions 322–355. Protein/peptide nucleic acid interactions 356–387. Protein/peptide lipid interactions …”

Section: Introductionmentioning

confidence: 99%

Survey of the year 2008: applications of isothermal titration calorimetry

Falconer

Penkova

Jelesarov

et al. 2010

J of Molecular Recognition

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Isothermal titration calorimetry (ITC) is a fast, accurate and label-free method for measuring the thermodynamics and binding affinities of molecular associations in solution. Because the method will measure any reaction that results in a heat change, it is applicable to many different fields of research from biomolecular science, to drug design and materials engineering, and can be used to measure binding events between essentially any type of biological or chemical ligand. ITC is the only method that can directly measure binding energetics including Gibbs free energy, enthalpy, entropy and heat capacity changes. Not only binding thermodynamics but also catalytic reactions, conformational rearrangements, changes in protonation and molecular dissociations can be readily quantified by performing only a small number of ITC experiments. In this review, we highlight some of the particularly interesting reports from 2008 employing ITC, with a particular focus on protein interactions with other proteins, nucleic acids, lipids and drugs. As is tradition in these reviews we have not attempted a comprehensive analysis of all 500 papers using ITC, but emphasize those reports that particularly captured our interest and that included more thorough discussions we consider exemplify the power of the technique and might serve to inspire other users.

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Chapter 4 Synthesis of molecular tweezers and clips by the use of a molecular lego set and their supramolecular functions

Cited by 6 publications

References 79 publications

Effect of molecular clips and tweezers on enzymatic reactions by binding coenzymes and basic amino acids

Effect of molecular clips and tweezers on enzymatic reactions by binding coenzymes and basic amino acids

Donor/Acceptor‐Substituted Chiral Molecular Clips – Synthesis and Host–Guest Complex Formation

Survey of the year 2008: applications of isothermal titration calorimetry

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